How old is the Universe?

The Universe is 13.75 billion years old, primordial helium has been spotted for the first time and key evidence for the inflationary period immediately after the Big Bang has been found. But not all the new discoveries by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) appear to fit cosmological theory.

Previously, scientists using data from WMAP measured the time since the Big Bang to be an incredibly precise 13.73 billion years (give or take 0.12 billion years). And now, using the same space-based observatory, the age of the universe has been refined even further, adding another 20 million years to the total.